The present invention relates to a device for appropriately measuring mechanical properties of elastic bodies such as mechanical properties of a skin.
Conventionally, as a device for measuring mechanical properties of elastic bodies such as a skin, there are known devices, such as a so-called Cutometer for bringing an adherent probe into close contact with the skin and sucking and exhausting a gas therefrom to measure a degree of deformation of the surface of the skin caused thereby, and a Twistometer for rotating a contact on a surface of the skin to measure a stress generated from the skin side in response to the rotation. In such devices, there are difficulties in that measurement cannot be performed taking into account directivity of the skin and quantitative measurement cannot be performed in the strict sense of the word. In addition, a force applied to the skin by these devices is not a force applied to the skin in a daily life.
As a device capable of measuring extending ability of the skin in an arbitrary direction, there is known an extensometer (Acta. Derm. Venereol. (Stockh), 1997, 77:416-419). However, the only mechanical property value that is measured by this device is extending ability.
The inventors have found that a collagen fiber structure exists in dermis of the skin and, therefore, there is a significant difference of mechanical properties according to directions. Therefore, meaningful mechanical property values cannot be measured in the skin unless directivity of measurement is controlled strictly. Moreover, the extensometer for pulling the skin to measure its extending ability is not regarded as an optimum machine for measuring mechanical properties in examining relationship between mechanical properties and wrinkle formation.
The present invention has been devised under such circumstances, and it is an object of the present invention to provide a device for measuring mechanical properties of elastic bodies that is capable of strictly controlling a direction of measurement and measuring mechanical properties or the like that are more related to wrinkle formation on a surface of an elastic body such as a skin.
In view of such actual circumstances, the inventors concentrated their efforts on researches and, as a result, found that such measurement is possible by using a device for measuring mechanical properties of elastic bodies that is capable of analyzing deformation of the skin due to an external force imitating a force that a facial skin of a human is actually subjected to in a daily life, that is, measuring and analyzing a stress of the skin when the skin is contracted. That is, the present invention relates to the following technology.
(1) A device for measuring mechanical properties of elastic bodies, comprising: at least two contacts adapted to contact a surface of an elastic body to be measured, at least one of the contacts being movable; a drive section for moving the movable contact; a control section for controlling an action of the drive section; a detecting section for detecting a stress generated by the movement of the contact as an electric signal; and a processing section for processing the electric signal for the stress detected by the detecting section and an amount of movement of the movable contact, in which the action of the contacts making contact with the surface of the elastic body includes a closing action of the two of the contacts and a stationarily holding action after the closing action.
(2) A device for measuring mechanical properties of elastic bodies according to (1), which further comprises a display section for displaying data processed by the processing section.
(3) A device for measuring mechanical properties of elastic bodies according to (1) or (2), wherein the elastic body to be measured is a skin.
(4) A device for measuring mechanical properties of elastic bodies according to any one of (1) to (3), wherein a probe is comprised of the contacts, the drive section and the detecting section, and the device comprises an arm section for holding a position of the probe.
(5) A device for measuring mechanical properties of elastic bodies according to any one of (1) to (4), which comprises a holding section for holding the elastic body to be measured.
(6) A device for measuring mechanical properties of elastic bodies according to any one of (1) to (5), wherein the contacts are fixed on the surface of the elastic body.